<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>04_JS流程控制</title>
</head>
<body>

    <script>
        //1.流程控制（顺序结构）
        console.log("1")
        console.log("2")
        console.log("3")

        //2.if结构
        let uname = 'sffsd';
        if(!uname) {
            alert('请先登录');
        }else {
            alert('登录成功,欢迎'+ uname+ '回来' );
        }

        //3.switch结构
        let gender = 0;
        switch (gender) {
            case 1:
                console.log('男');break;
            case 0:
                console.log('女');break;
                default:
                console.log('未知');
        }

        //4.循环结构
        let names = ['张三','李四','王五'];
        for (var i = 0; i < names.length; i++) {
            console.log(names[i]);
        }
        console.log('循环结束');
        console.log('i的值是'+ i);

        //5.增强for循环
        for (let n of names) {
            console.log(n);
        }



    </script>


</body>
</html>